Electrode clamp



NOV. 1, 1938. W, E. MOQRE 2,135,408

ELECTRODE CLAMP Filed April 24, 1936 2 Sheets-Sheet l zz' 25H 1a Il lll H116 W, E. MOORE ELECTRODE CLAMP Nov. 1, 1938.

Filed April 24, 1936 2 Sheets-Sheet 2 ///////////////////////////////////////fmlv Patented Nov. l, 1938 UNITED STATES PATENT OFFICE ELECTBODE CLAMP Application April 24, 1936, Serial No. 78,280

7 Claims.

This invention relates to improvements in clamps and more particularly to electrode clamps and supporting arms for use with the electrodes of electric arc furnaces.

In electric arc furnaces using large electrodes to carry heavy current, or having electrodes which because of their composition have an irregular surface, the usual types of ring electrode clamps cannot be used successfully because of the dliliculty in obtaining a large surface contact with that type of clamp and consequent frequent burning out of the clamps. An important object of the present invention is the provision oi' an electrode clamp which can be used effectively with.v electrodes carrying heavy currents and which will have a large surface contact with the electrode regardless of irregularities on the surface of the electrode.

Another object of this invention is to provide an electrode clamp which is adjustable to nt electrodes of different sizes and which will adapt itself to irregularities on the surface of the electrades.

A further object of this invention is the provision of an electrode clamp which will effectively conduct current to the electrode and which will effectively cool the electrode.

Still another object of my invention is the provision of an electrode clamp which can be lowered into a position very close to the charge while its parts are protected from the heat of the charge and cooled, and which can be adjusted to permit slipping of the electrode to change its position in the clamp.

Other objects and advantages of this invention will be apparent during the course of the following description.

In the accompanying drawings, wherein like characters of reference denote like or correspond- 40 ing parts throughout the same- Figure 1 is a side elevation 'of an electrode clamp embodying this invention, showing it in position on an electrode,

Figure 2 is a top plan view thereof, parts being removed and parts being shown in section,

Figure 3 is an end elevation showing the disk for connection to the flexible cable terminals and the cooling water supply.

Figure 4 is a section on the line 4 4 of Figure 3,

Figure 5 is an elevation of one of the contact shoes oi' the clamp,

Figure 6 is a vertical sectional view thereof,

Figure 7 is a top plan view of one of the contact shoes,

Figure 8 is a top plan view of several of the contact shoes showing the chain and chain tightener in position thereon, parts being broken away,

Figure 9 is a fragmentary elevation showing the chain tightener in position on the contact shoes,

Figure 10 is an elevation of the chain tightening yoke,

Figure 11 is an elevation of the chain buttress link,

Figure 12 is a fragmentary sectional view showing the connection of the bus bars with the conductor tubes, and,

Figure 13 is a cross section through a portion 'of one of the contact shoes and chain protecting cuff.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of this invention, the numeral i6 designates an electrode of any suitable composition and for use with any type of arc furnaces. These electrades are circular in cross section, and in large reduction furnaces they are often ceramic, being a mixture of carbon and pitch ground together, extruded and baked to carbonize the pitch so that it will not melt when the electrode is heated. Consequently the outer surface of an electrode of this type is usually irregular and it is difficult to obtain a good electrical contact with its surface. Electrodes of all types are of different sizes, and there is found to be a slight variation in the diameters of electrodes of the same size. It is essential that the electrode clamp fit the electrode to produce a good surface contact, especially when heavy currents are being used, and this contact is also essential for proper cooling of the electrode.

In the present invention the contact portion of the clamp is formed by a plurality of contact shoes I6 which are of generally arcuate shape and which are independent of each other. The shoes I6 are each of generally rectangular hollow formation, and are provided at their lower ends with laterally projecting hollow portions Il forming a continuation of the bottom portions of the shoes. Screw threaded openings I8 in the tops of the portions i'l communicate with the interior of the shoes. A centrally arranged partition I9 extends from the top of each shoe to a point adjacent the bottom thereof, and two partitions 2U extend from the bottom of each shoe to points adjacent its top, thereby forming a tortuous passage through the shoe from one opening I8 to the other. Suitable cleanout openings closed by plugs 2| are provided in to top and bottom of each shoe, and the shoes are formed of a suitable electrically conducting material such as high conductivity copper.

Each shoe is provided on its outer surface midway between the top and bottom thereof with a transverse chain receiving and protecting cuff 22 which preferably extends laterally beyond the side edges of the shoe. In use, the shoes are arranged in spaced relation to form a circle to receive the electrode, as indicated in Figures l, 2 and 8, and are clamped about the electrode by a suitable chain 23 which passes through the cuffs 22 and engages the outer surfaces of the contact shoes. Chain 23 is in the form of a link belt or flexible web having substantial width and made up of thin flat links of some suitable heat resistant and non-magnetic material such as austenitic steel. The chain is preferably formed in two separate sections, one of which is provided at each end with a clamping bolt 24, and the other of which is provided at each end with a buttress link 25 to receive the clamping bolts 24.

Each of the clamping bolts comprises a screw threaded shank having a yoke 26 adapted to straddle the cuff 22 of the adjacent shoe and having slots 21 to receive the end links of the chain 23 which are pivotally secured to the yoke by means of a pin 28. The buttress links 25 are each provided with an opening 29 to receive the shanks of bolts 24 and with a dished recess surrounding one end of the opening 29 to serve as a seat for the curved end of the clamping nut 30 which receives the end of the bolt shank. 'I'he contact shoes i6 are provided with enlarged cuffs 22' to receive and protect the buttress links, clamping bolts and clamping nuts, as indicated in Figures 1, 2 and 8.

Nuts 30 may be operated by suitable socket wrenches or the like to tighten chain sections 23 and clamp the contact shoes about the electrode l5. It will be noted that the shoes i6 are flexibly hung by flexible pipes of sufficient length to permit free, independent action of the shoes which can therefore adjust themselves to fit the surface of the electrodes. The arrangement of the chain 23 at the center of the shoes permits independent pivoting or rocking of the shoes about the chain, permitting the contact shoes to adjust themselves to the surface of the electrode.

The inner concave surface of each contact shoe is formed to provide maximum surface contact with the electrode regardless of variations in the diameters of the electrodes. 'I'he contact surfaces of the shoes I6 and l5' are relieved at their central portions, as indicated at A-B in Figure 7. The arc from A to B has a radius which is smaller than the radius of the arcs A-D and B-C, the radius of A-B corresponding to the radius of the minimum size electrode while the radius of arcs A-D and B-C correspond to the radius of the maximum size electrode. In this way electrodes approaching the minimum size will have a substantial segmental contact with the shoe surface from A to B while electrodes approaching the maximum size will have a substantial segmental contact with the surface A-D and B-C. 'I'he smallest possible contact with this type of contact surface is a two line contact at A and B. In contrast to this construction, the usual clamps are made to ilt the maximum diameter electrodes and consequently have a single line contact with electrodes varying from a maximum diameter.

A pair of spaced bus tubes 3i are formed of strong copper tubing and are bent into rings which surround the electrodes above the contact shoes. The ends of the bus bars extend in spaced parallel relation away from the ring portion and extend into a contact disk 32. Reinforcing webs or battens 33 connect the spaced portions of the bus bars at spaced points. Two bus bars are preferably provided spaced one above the other and connected by battens 34. The disk 32 is hollow and is divided into two chambers by a horizontal partition 35. The two ends of the upper bus bar extend within the chamber above the partition 35 while the two ends of the lower bus bar extend into the chamber below partition 35. A cover plate 36 closes the interior of the disk 32, and a pair of water circulation nipples 31 are screw-threadedly received in openings in the cover plate, one of the nipples communicating with each of the disk chambers, as seen in Figures 3 and 4. A plurality of tapered openings 38 are arranged in a circle adjacent the periphery of the disk 32 and receive the ends of terminals 39. Extremely heavy currents may be carried by the disk and bus bars by using a large number of these terminals fitting in the openings 33.

The contact shoes I6 and I6' may be supported from the spaced bus bars by means of suitable metal straps 40. One strap supports each contact shoe, being bolted thereto at 4I, and alternate straps are supported by different bus bars to distribute the weight of the electrode between the bus bars. Strong, flexible conductor tubes 42, perferably of deoxidized copper, connect the upper bus bar with one end portion I1 of each contact shoe while similar conductor tubes 43 connect the lower bus bar with the other end portion I1 of each contact shoe. The lower ends of the conductor tubes 42 and 43 are screwthreadedly received in the openings i8 in the projecting end portions l1 of the contact shoes IE while the upper ends of these tubes are provided with collars 44 rigidly secured thereto, and with nuts 45 slidably arranged on the tubes below the collars 44. Hollow screw-threaded studs 46 extend into the bus bars, being welded thereto, and are received in the nuts 45. The upper ends of conductor tubes 42 and 43 and of the collars 44 are convex while the lower ends of the studs 4G are concave to assure a water tight seal when the nuts 45 are tightened. Conductor tubes 42 and 43 being flexible, are easily shaped or formed to the desired shape, as seen in Figure l, and shaping of these tubes will not affect the water tight seal of the tubes with the studs 46.

'Ihe flexible conductor tubes are connected to the lower ends of the contact shoes, thereby providing a maximum length of flexible tubing between the contact shoes and bus bars to permit the utmost freedom of movement to the contact shoes in adjusting themselves to the contour of the electrode.

An insulating hanger 41 is connected to the bus bars at each side of the electrode by means of straps 48 looped under each of the bus bars to distribute the weight of the electrode. Sultable ears 49 are provided at the top of the contact disk 32 and suitable cables may be connected to the ears 49 and hanger 41 to support the electrode and adjust it relative to the furnace. Obviously other suitable means may be provided for supporting the electrodes and adjusting their po` sition.

In operation the clamp is placed over an electrode and the two nuts 30 operated to tighten the chain 23 and clamp the contact shoes about the electrode. The contact shoes are free to adjust themselves to the contour of the electrode surface, and because of the relieved contact surfaces of the shoes will provide a maximum surface contact despite variations in the diameter of the electrodes. Current passes from the terminals 39 through the disk 32, bus bars 3| and conductor tubes 42 and I3 to the contact shoes and electrodes. Because of the individual self adjusting contact shoes, a large contact surface between the contact shoes and electrode will be obtained, and burning out of the shoes due to poor contact and the use of heavy current will not occur. Cooling water enters disk 32 through one of the nipples 31 and passes through one of the bus bars to the conductor tubes, and through the contact shoes and conductor tubes to the other bus bar and out through the contact disk and other nipple. The connections at the tops and bottoms of the conductor tubes are water tight and the large contact area between the shoes and electrode assure eilicient cooling of the electrode.

By attaching the adjusting bolts 24 to the ends of the same chain section, they can be adjusted from the same side of the electrode, as indicated in Figure 2. The chain 23 and clamping bolts are protected from the heat of thefurnace by the cuffs 22 and 22. This protection is especially important when the clamp is used with open top furnaces, and if desired, the cuffs may be extended for use with such furnaces to completely cover the chain.

The clamp of this invention is particularly effective when used with open top furnaces and with large electrodes. Due to the fact that the clamp is suspended or hung from the bus tubes 3|, the clamp may be operated much closer to the charge than the clamps of the prior art, and consequently electrodes of smaller diameter may be used.V The non-magnetic steel chain 23 reinforces the shoes I6 and takes up the stress and weight incident to supporting theelectrode. Without the reinforcement provided 'by the use of this chain, the shoes would be likely to break when highly heated due to the fact that the shoes are usually formed from copper or similar conductive material which becomes brittle at high temperatures. y

While I have shown and described the preferred embodiment of my invention, it is to be understood that various changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of my invention or the scope of the subjoined claims.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. An electrode clamp comprising a plurality of independently and freely movable contact shoes, a flexible member engaging said contact shoes and adapted to clamp them about an electrode, and means to conduct electric current to the contact shoes.

2. An electrode clamp comprising a plurality of independently and freely movable contact sections, said contact sections being of generally arcuate shape and having their contact surfaces relieved throughout a portion of their width. and a ilexible member engaging the contact shoes about their mid-sections and serving to clamp the shoes about an electrode, said contact shoes being free to rock about the iiexible member.

3. An electrode clamp comprising a terminal member having connections with a source of electricY current and a sourceV of a. cooling medium, a bus bar having its ends connected to said terminal member and being formed into a loop to surround an electrode, a plurality of contact sections suspended from the -looped portion of said bus bar, means to clamp said contact sections about an electrode, and riiexible conductors connecting the contact sections with the loop portion of the bus bar to conduct electric current and a cooling medium to the contact sections.

4. Air-electrode clamp comprising a bus bar connected to a source of electric current and a source of a cooling medium, said bus bar having a looped portion adapted to surround an electrode, a plurality of substantially arcuate contact shoes suspended from the looped portion of the bus bar, said contact shoes having passages therethrough for the reception of a cooling medium, and exible conductors connecting the looped portion of the bus bar to the lower portions of the contact shoes to conduct electric current and a cooling medium to said contact shoes.

5. Anrelectrode clamp comprising a pair of bus bars having connections with a source of electric current and a source of a cooling medium, said bus bars having looped portions adapted to surround an electrode, a plurality of contact shoes suspended from said bus bars, flexible conductors connecting said bus bars to the lower portions of said contact shoes to conduct electric current and a cooling medium to said contact shoes, and means to clamp said contact shoes about an electrode.

6. An electrode clamp comprising a plurality of substantially arcuate contact shoes, a exible chain adapted to surround said contact shoes to clamp them about an electrode, said chain being formed in two sections, clamping bolts secured to the ends of one of said chain sections, buttress links secured to the ends of the other chain section and adapted to receive the Vclamping bolts on the first named chain section, and cu's on said contact shoes to surround and protect the flexible chain, said cuffs each being open at one end and being spaced from the clamping bolt to permit the insertion of a bolt operating tool.

7. An electrode clamp comprising a plurality of generally arcuate substantially independently movable contact shoes, a flexible clamping member engaging the contact shoes about their midsections and serving to clamp the shoes about an electrode, said contact shoes` beingY free to rock about the flexible clamping member, and means to conduct electric current to the contact shoes.

WILLIAM E. MOORE. 

